Subsurface signal transmitting apparatus

ABSTRACT

The subsurface signal transmitting apparatus ( 10 ) including an insulation coupler ( 11 ), a carrier device ( 12 ) for mounting the telemetry instrumentation ( 75 ), and a by-pass system for avoiding pressure build-up either above or below the apparatus. The insulation coupler ( 11 ) includes a housing member ( 13 ) having a central opening ( 16 ) defined by an interior surface ( 22 ) extending in the longitudinal direction and a mandrel member ( 14 ) having an exterior surface ( 32 ) spaced from the interior surface ( 22 ) of the housing member ( 13 ) to provide a gap or clearance ( 33 ) with an insulating bonding material ( 29 ) occupying the clearance. The surfaces are oriented so that when the coupling is in tension at least a portion of the two surfaces that when the coupling is in tension at least a portion of the two surfaces experience interacting forces towards each other in he longitudinal direction of the coupling and in event of failure of the bonding material, the mandrel member is unable to withdraw from the housing member. The by-pass system includes a by-pass tube ( 120 ) which extends through central openings ( 2, 61 ) of the insulation coupler ( 11 ) and carrier device ( 12 ) and provides for electrically insulating one end of the assembly from the other but allows for pressure equalization via a fluid passage-way ( 121 ). The carrier device ( 23 ) has a cylindrical body ( 57 ) forming external channels ( 74 ) for concealing instruments ( 75 ) about its circumference.

TECHNICAL FIELD

[0001] This invention relates to a subsurface signal transmittingapparatus of the type for sensing certain conditions in a bore hole andthen transferring them to a surface located receiver.

BACKGROUND ART

[0002] In the oil industry, it is necessary to obtain and analyzedown-hole conditions, such as pressures and temperatures at variouselevations. This has been done most commonly in the past by loweringelectrically or mechanically operated gauge devices into the well, thesegauges being either suspended on a wire line or fastened to availableoil well tubular sections. By utilizing conductor wire lines, theinformation can be transmitted to the surface on a “real-time” basis.When non-conductor lines are employed, the gauge must be withdrawn tothe surface so that the data can be either down-loaded to a plotter orread directly from an internally scribed chart, thus providing theoperator with the desired information. In this process, whether the wireline is used as a suspension member or is strapped to the outside oftubular sections forming a string in the bore hole, damaging of the wireline is not uncommon. The damage or destruction of the wire line canoccur when the string of tubular sections sticks within the bore hole,or when the wire line and/or tubing string is being run in or out of thehole. Not only is there the cost of the lost equipment, but such damageadds significantly to the cost of the operation because of the timeinvolved in repairing the equipment and in fishing the equipment fromthe hole. The process of having to fish also includes the risk ofendangering the well itself.

[0003] Other techniques have been developed for transmitting signalswhich are produced by apparatus located down-hole to the surface,including devices which develop and transmit signals electromagneticlyto the surface. Such signals having been received by a receivingapparatus provide instantaneously information on the conditions senseddown-hole. This telemetry technique involves locating down-holerelatively complex equipment and providing a source of power. Structureshave been developed for containing such equipment and power source.These structures enable the use of a portion of the tubing string tofunction as an antenna in the transmission of the signals to thesurface. The process of using the tubing string, such as the upperportion of the string, as the antenna involves the provision of aconnection which electrically isolates the upper portion from a lowerportion of the tubing string so that the output voltage of the down-holeelectromagnetic transmitters can be connected across terminals which areelectrically isolated from each other.

[0004] The approach of using a telemetry technique for transmitting theinformation to the surface provides instantaneous readings at a setlocation of the down-hole sensing equipment and also avoids the use of awire line. While having significant advantages over other techniques,problems due to the conditions which exist in the bore hole have in manyrespects hindered successful development in this process. For example,although there exists insulation couplers for use in an arrangementwhere the upper portion of the tubing is used as an antenna, suchcouplers have not always functioned satisfactory when the lower portionof the tubular string becomes jammed in the bore hole. This is notuncommon particularly where the lower part of the bore hole deviatesfrom the vertical. Present insulation couplers have not been known towithstand the application of a high torque used in attempting to forcethe string when jammed, and a severing of the tubing string at theinsulation connector results in the lower portion of the tubular string,which houses the expensive telemetry sensing and telemetry equipment,becoming completely disconnected at its down-hole position. Not only isthe cost of the equipment involved, but there is the expense involved inreopening the hole and potential damage to the well.

[0005] Moreover, due to the nature of the sensing, power source andtransmitting equipment utilized in the telemetry process and the extremeconditions to which the down-hole end of the tubing string is subjected,known methods of mounting such equipment has not always provedsatisfactory. While the equipment must be protected, the manner in whichit is carried and its connection to the insulation connector must besuch that it is readily available for exchanging and servicing.

[0006] Yet another characteristic of some known structures incorporatingan insulation coupler is that they are not capable of coping withparticular conditions which can develop either above or below the testequipment when located down-hole. The down-hole test equipment isfrequently used in conjunction with annular sealing packers, and in theknown structures the insulation connector and/or the test equipment andmounting elements, together with the sealing packers in effect form acomplete seal or blockage in the bore hole. Accordingly, in the event apressure build-up develops either above or below the sealing packers,the tubing string can be sucked into or blown out of the bore hole. Thiscan happen with sufficient force to cause severe injury to personnel anddamage to equipment.

DISCLOSURE OF INVENTION

[0007] It is an object of the present invention to provide an apparatusfor subsurface telemetry signal transmission which overcomes the abovedescribed disadvantage of known devices presently available in thistechnology.

[0008] According to one aspect of the present invention, which residesin a connector assembly for connection in a tubing string in a borehole, the connector assembly electrically insulates an upper section ofthe string above the connector assembly from a lower section below theconnector assembly. The assembly includes an outer housing member and aninner mandrel member.

[0009] In one form of the connector assembly the housing member hasconnection means adjacent one end of the connector assembly forattachment of the one end to one of the above mentioned sections of thestring, and the housing member has an internal surface portion definingan opening tapering outwardly in cross-sectional area toward that end ofthe connector assembly. The mandrel member has connection means adjacentthe other end of said connector assembly for attachment of that end ofthe connector assembly to the other of the above mentioned sections ofthe tubular sting, and the mandrel member has an exterior surfaceportion tapering outwardly in cross-sectional area away from that end ofsaid connector assembly. The exterior surface portion of the mandrelmember is disposed within the interior surface portion of the housingmember and provides a clearance between said surface portions. Theconnector assembly further includes an electrically non-conductingbinder material disposed within the clearance.

[0010] It is apparent that in the use of this form an insulationconnector of the present invention, the outer housing, which may beconnected to the upper portion of the tubular string, for example, canfunction as an antenna for transmitting signals received from equipmentmounted in a carrier section connected to the mandrel member. In thecase of a tension force being applied to the connector assembly, shearforces are developed in the binding located in the clearance, but thebinding is also in compression between the two tapered surface portionsof the housing and mandrel members. Moreover, because of the directionof taper relative to the connection means at the opposite ends of theconnection assembly, the mandrel member cannot be pulled through thehousing member due to an excessive tensional pull on the tubular string.Even on failure of the binding in the clearance, the tensional pullresults only in the surface portions moving towards an engagingposition.

[0011] In another form of the present invention, the housing member hasa first connector means adjacent one end of the connector assembly forattachment to an adjacent tubular section of the string above theconnector assembly and the inner mandrel member has a second connectionmeans for attachment to an upper end of an instrument carrier device,the mandrel member being of tubular form defining a central passagewayextending from said one end to said other end of said connectorassembly. Means is provided for electrically insulating the housingmember from the mandrel member. The carrier device includes an elongatedtubular member having channels in the exterior surface thereof foraccommodating instrument sensing units. The tubular member also has aninternal passageway disposed therein and placing a lower end thereof incommunicating with said passageway in said mandrel member at the upperend thereof. The tubular member has a third connection means at a lowerend thereof for attachment of the carrier device to an adjacent sectionof the tubing string below said carrier device. An electricallyinsulating by-pass tube extends through the passageways of said mandreland said carrier device and has fourth and fifth connector means atupper and lower ends thereof, respectively, for connection of theby-pass tube to the tubular sections above and below the apparatus, thuspermitting fluid passage through said apparatus.

[0012] In this structure, the by-ass tube extending through thepassageways in both the connector assembly and the carrier deviceprovides for fluid communication past the subsurface transmittingapparatus so that pressure build-up either above or below the apparatusis prevented, and accordingly the destructive results which can resultfrom such build-up is avoided.

[0013] According to another aspect of the invention, there is provided acarrier device for use in a subsurface signal transmitting apparatus,the carrier device being in the form of an elongated body member havinga generally cylindrical outer surface. A first connection means islocated at one end of said body member for attachment of the body memberto an insulation connector assembly having an outer housing memberelectrically insulated from the body member. The body member has definedin the outer surface thereof a plurality of longitudinal channelscommencing adjacent the one end and extending towards an opposite end ofsaid body member. Means are provided for detachably securing instrumentsensing units individually within the channels, and a passage extendsfrom said channels to the one end of the body and accommodates a signaltransmitting cable extending from the units for electrical attachment tothe outer housing of said insulation connector assembly.

[0014] The carrier device is capable of being attached to an end of aninsulated connector assembly, such as that described above, and moreparticularly to the connection means provided by the mandrel, so thatsensing units which include a transmitting component, can be readilyinserted and retrieved from the channels in which they are protectedfrom damage by engagement of the carrier with the sides of the borehole. The cable which carries the signals to be transmitted can then belocated in the provided passage and connected to the antenna providingmember of the connection assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the accompanying drawings which show an embodiment of theinvention, as example,

[0016]FIGS. 1A, 1B, 1C, 1D, 1E and 1F, when viewed in end-to-endcombination as indicated, shot-' a side cross-section view of thesubsurface transmitting apparatus of the present invention, and

[0017]FIG. 2 is a perspective, exploded view of the carrier deviceforming part of the apparatus of FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Referring now to FIG. 1, wherein like reference numbers denotelike elements descried herein, the reference number 10 denotes theoverall subsurface transmitting apparatus in which the present inventionis incorporated. In FIG. 1B and 1C, there is shown an insulation coupler11 and in FIGS. 1C to 1F, as well as FIG. 2, there is shown a carrierdevice 12 of a preferred embodiment of invention. In use, the apparatus10 is connected at its upper end to a lower end of tubing string (notshown) which is lowered into the bore hole for taking readings ofconditions in the bore hole, such as pressure, temperature, relativeangle, etc. The readings are transmitted to a receiver at the surfacenear the top of the bore for recording and analysis by the operator. Theapparatus may also be used to compute other information in relation tothe equipment status, i.e. the status of various down-hole components,such as valves, safety joints, etc. The tubular string includes othersections which are connected to the lower end of the apparatus 10, andthese may include, for example, sealing packers (not shown).

[0019] The insulation coupler 11 is in the form of a connector assemblyhaving an outer housing member 13 and inner mandrel member 14, both ofwhich are formed of metal (FIG. 1B). The outer housing member 13 has anouter cylindrical surface 15 which is preferably of the same diameter ofthe other sections in the tubular string, and it is hollow so as toprovide a bore or opening 16 extending therethrough. The opening 16 isof maximum cross-section at its upper end where there is provided aconnection means in the form of internal threads 17 for attachment ofthe outer housing member 13 to a tubular section 20, which has anexternally threaded lower end portion 21 of reduced diameter.

[0020] Below the internally threaded upper end of the outer housingmember 14, the bore or opening 16 is defined by internal surface 22which tapers outwardly from the lower end towards the connection meansprovided by the internal threads 17. The surface 22 is preferably in theform of a conic frustum and wherein the gradient or degree of taper isslight so that the outward taper in cross-section of this portion of theopening 16 is relatively gradual. Below the tapered portion of theopening 16 is a lower portion 23 of the opening 16 which is of lessdiameter, of course, than the cross-section of the internal threadedportion at the upper end. Substantially along the length of the surfacedefining the lower portion 23 are a plurality of circumferentiallyspaced, longitudinally extending grooves 24 which are substantiallysemi-circular in cross-section. At the very lowermost end of the outerhousing section 13, the internal bore or opening 16 is enlarged toprovide annular enlarged bore defining a seat 25 for a sleeve 65.

[0021] The inner mandrel member 14 is mainly received within the opening16 of the outer housing member 13. It has a lower or tail portion 26(FIG. 1C), which is of smaller diameter than its upper end, and thelower portion 26 has external threads 27 which provide connection meansfor attachment to the upper end of the carrier device 12. The mandrelends in an end surface 28. The mandrel member 14 is of tubular form andhas an opening or bore 30 extending longitudinally therethrough. Thebore 30 is of uniform diameter except for a seal receiving enlargement31 at its upper end. The upper end portion of the mandrel member 14 hasan outer surface 32 which tapers outwardly in a direction away from theconnector means provided by the threaded lower portion 26. The size ofthe tapered portion of the mandrel is selected to substantially fill thetapered portion of the opening 16, and the taper is such to match thatof the tapered openings, i.e. the gradient or degree of the outersurface 32 which is also a conic frustum is substantially the same asthat of the surface 22. When mounted in an assembled condition withinthe outer housing member a slight gap or clearance 33 remains betweensurfaces 22 and 32. The thickness of the clearance 33 is substantiallyconstant and is in the order of 0.040 inch.

[0022] Although the degree of taper of the surfaces 22 and 32 is notgreat, the cross-section area of the mandrel adjacent the upper end ofthe taper is significantly greater than the cross-sectional area of theopening 16 in the outer housing member 13 adjacent the lower end of thetaper of the opening 16.

[0023] Below the tapered surface 32, the mandrel member 14 has acylindrical portion 34 which has circumferentially spaced,longitudinally extending grooves 35, which are also of substantiallysemi-circular shape in cross-section. The grooves 24 of the housingmember 13 and grooves 32 of the mandrel member 14 align to form aplurality of longitudinal channels or openings, which are substantiallycircular in cross-section. Each longitudinal opening thus formed haslocated therein a pin or rod 36 which is also of circular cross-sectionand of a diameter to fill the longitudinal opening provided by grooves24 and 35. The rods are formed of an electrically insulating material,such as a tough plastic material which has a significant shear strength.

[0024] The tubular section 20 which is connected to the upper end of theouter-housing member 12 is a substitute connector in that its upper endhas an internally threaded tapered bore 37 (FIGS. 1A and 1B) forreceiving an externally threaded lower end portion 40 of a tubularsection 41. An internal central bore 42 extends through the tubularsection 20, the lower portion of the bore 42 being enlarged at 43 to thesame dimension as the enlarged bore 31 in the mandrel member 14 (FIG.1B). The upper end of the enlarged bore in tubular section 20 terminatesat a radial shoulder 44, and the lower end of enlarged bore 31 in themandrel member 14 terminates in a radial shoulder 45. A sleeve 46 of arigid durable material, which is of a electrically insulating material,is disposed with its opposite ends engaged by the opposed radialshoulders 44 and 45. The diameter of an internal passage 47 in thesleeve 46 is of substantially the same dimension as the bore 30 on themandrel member 14. O-ring type seals 50 and 51 are disposed in annulargrooves formed in the interior surfaces of the enlarged bores 31 and 43of mandrel member and tubular member 20 to ensure a seal between thesleeve and these members. The upper end of the mandrel member 14 and thelower end of the tubular member 20 are each provided with recessed areaswhich receive a pair of annular seals 52 and 53, which are, of course,of an electrical insulating nature and provide a seal at the upper endof the mandrel member.

[0025] Accordingly, the outer housing 13 and the mandrel member are notin direct contact with each other, and the mandrel member 14 is not indirect contact with the tubular member 20 which is made of metal and isin direct contact with the outer housing 13. Any member which is incontact with both the outer housing member 13 and the mandrel member 14or in contact with both the mandrel member 14 and the tubular member 20are formed of electrically insulating material.

[0026] The inner tapered surface 22 of the outer housing member 13 andouter tapered surface 32 of the mandrel member 14 are separated adistance equal to the thickness of the clearance 33. This clearance isfilled with a bond material 29 which is of an insulating nature and hasconsiderable strength, such as an epoxy. When the shoulder 45 mandrel isheld in abutment with the lower end of the sleeve 46, the mandrel memberand the outer housing are positioned correctly relative to each other toprovide a controlled clearance 33. The bond material 29, then in aliquid form is injected through an opening 54 in the housing member 13,and the material” completely fills the clearance and passes down intothe spaces adjacent the rods 36. At the upper end, the liquid epoxy isretained by seals 50 and 51. The material 29 then sets to provide arigid bond connection between the tapered surfaces 22 and 32 capable oftransferring normally experienced torque forces between the outerhousing member 13 and the mandrel member 14. The bond connection betweenthe tapered surfaces 22 and 33 is also capable of transferring forcesthrough the insulation coupler in the longitudinal direction, such asthe weight of the portion of the tubular string below the apparatuswhich places the bonding material in shear and also in compression asthe mandrel member 14 is pulled down relative to the housing member 13.

[0027] In the event of extremely high torsional forces such as in theevent of the lower part of the tubular rod becoming jammed, or shouldthe bond material 29 start to fail. Torsional forces are transferablefrom the outer housing member 13 to the mandrel member 14 by way of therods 36 contained in the groove 24 of the housing member and the grooves35 of the mandrel member. Of importance in the insulation connection isthe direction of the slopes of the surfaces 22 and 32 in relation to theconnection means provided by the threaded ends of the housing member 13and the mandrel member 14. In an upward pull of the tubular string fromthe bore, such as when a lower portion of the string below theinsulation coupler 11 becomes jammed, and this pulling force may occurin combination with a torsional exertion, the bonding material in theclearance, while experiencing shear forces is also in a state ofcompression between the surfaces 22 and 32. Furthermore, in event offailure of the bonding material, the mandrel member cannot disconnectfrom the housing member as in the longitudinal directions, the surfacescan simply move toward an engaging position. Accordingly, the costlysituation which Occurs when the lower portion of the tubular stringbecomes separated and lodged in a down-hole location is avoided.

[0028] It is apparent that the insulation coupler 11 could beconstructed in a manner to be inserted in a tubular string in aninverted orientation and still utilize the basic principle shown in theillustrated embodiment. With obvious modifications, the housing membercould be adapted to be connected to the carrier device with the mandrelmember, which is electrically isolated from the housing member, beingconnected to the tubular member above the coupler. The relationshipbetween the tapered surfaces of the two members would still be such thatthe members could not be separated by an extreme longitudinal pull onthe coupler.

[0029] At the lower end of the outer housing member 13, there isprovided a plurality of screws one of which is shown at 55 threaded intoa hole in the outer surface of the housing member (FIG. 1B). A shortgroove 56 extends from each screw to the lower end of the housing member13. This provides a terminal connection for an output cable 57 (FIG. 2)extending from the signal transmitter equipment carried by the carrierdevice 12. Because the outer housing member 13 is insulated from thecarrier device and the tubular members carried therebelow, the outerhousing and the sections in the tubular string thereabove function as anantenna for the transmitted signals.

[0030] As previously described, the lower portion 26 of the mandrelmember 14 is attached to an upper end of the carrier device 12 whichincludes an elongated, generally cylindrical body 57 (FIG. 1C). The body57 has an outer surface 60 which is preferably of the same outerdiameter as the other tubular members of the string, and it is oftubular form having a longitudinal bore 61 is generally of the samediameter as the bore 30 of the mandrel member 14. The upper end of thebore is enlarged and is provided with internal threads 62 for threadedreception of externally threaded lower portion 26 of the mandrel member14. The lower end of the enlarged portion of the bore at the upper endof the body 57 provides a shoulder 63 against which the end surface 28of the mandrel member 13 engages so as to provide a sealed joint. Thereis further provided an annular groove 58 in the enlarged bore betweenthe threads 62 and the shoulder 63, which groove receives a seal 59.

[0031] At the very upper end of the body member 57 there is an enlargedbore 64 which is of the same diameter as bore 25 in the lower end of thehousing member 13. While the lowermost end surface of the housing member13 and the uppermost end surface of the carrier device 12 are spaced, asleeve 65, which is formed of an electrically insulating material, spansthe space and has opposite ends thereof received in the enlarged bores25 and 64. Within the seat 25 of the housing member 13, there is anannular groove 66 (FIG. 1B). Opposite the groove 66, there is providedan annular groove 67 on the exterior surface of the mandrel member 14.The grooves 66 and 67 contain seals 70 and 71 which engage the exteriorand interior surfaces, respectively, of the end of the sleeve 65extending into the seat 25 of the housing member 13. These seals retainthe epoxy at the lower end of the insulating coupler 11, when thebonding material is inserted into the clearance 33. The enlarged bore 64in the upper end of the body 57 is also provided with an annular groove72 which receives a seal 73 so as to provide a sealed connection betweenthe insulating sleeve 65 and the body 57 (FIG. 1C).

[0032] Defined in the outer surface 60 of the body 57 are a plurality oflongitudinally extending grooves or channels 74 which commence a shortdistance below the upper end of the body 57 and extend substantially tothe lower end thereof. The channels 74, which may number four, arecircumferentially spaced about the body 57 and are shaped incross-section to closely receive a sensing instrument or battery pack 75either of which are designed in the form of an elongated member 76having an outer or lower end 77 of reduced cross-section (FIGS. 1F and2). The upper end of the instrument or battery pack has a threaded maleportion which screws into a terminal block 80 (FIG. 1C). Each channel 74has a widened portion 81 at its upper end for receiving the terminalblock 80 which is wider than the instrument or battery pack 75. Thewidened portion 81 further has opposed recesses for receiving opposedears 83 of the terminal block 80 (FIG. 2). The ears 83 are provided withholes to receive screws 84 which are threaded into threaded openings inthe bottom of recesses so as to secure the terminal block and the upperend of the instrument or battery pack which is fastened thereto withinthe channel 74.

[0033] Passages or channels 84 interconnect the widened portions 81 ofthe channels 74, the channel 84 may receive cables for electricallyinterconnection of the terminal blocks. A channel 85 extendslongitudinally from at least one of the widened portions 81 of thechannel 74 to the upper end of the body 57. The channel 85 can bealigned with the short channel 56 at the bottom of the insulated housingmember 13 50 that the cable 57 can be accommodated for connection toscrew 55 threaded into the housing member 13. The housing member 13 andthe tubular section 20 and other sections thereabove, which are notinsulated from the housing member, as previously described, may functionas an antenna for transmitted information from the instrumentationmounted in the carrier device 12.

[0034] As can be seen in FIG. IF, there is provided at the lowermost endof the cylindrical body 57, a portion 86 of reduced diameter, and nearthe lower end of the portion 86 there are provided external threads 87.A tubular member 92 in the form of a substitute connector is threadedonto the outer end of the portion 86 by way of internal threads 90 in anenlarged bore 91 at the upper end of the tubular member 92. A lower endportion 93 of the tubular member 27 of reduced diameter is externallythreaded for reception in an internal threaded portion of adjacentmember of the tubular string below the apparatus 10. A bore 94, which issubstantially the same diameter as the interior bore 61, extendslongitudinally through the tubular member 92. Within the enlarged bore91 above the internal threads 90 is an annular groove 95 which containsa seal 96.

[0035] The portion 86 which is of reduced diameter at the lower end ofbody 57 extends over the lower ends of the channels 74. A collar or ringmember 97 which has an internal diameter only slightly larger than theouter diameter of the portion 86 is positioned between an upper endsurface 100 and a shoulder 202 provided at the top of the portion 86.The ring member 97 is free to turn on the reduced portion 86 but thereis provided a set screw 102 threaded through the ring and positioned toenter a radial bore 103 in the body 57 so as to lock the ring againstrotation in a set position when the set screw 102 is turned in. Theupper end portion of the ring member has an enlarged internal diameterto provide a skirt portion 104 having an internal surface 105. Theinternal diameter of the internal surface 105 is sufficient that itengages and encompasses the reduced lower ends 77 of the instrument orbattery packs 75, thus normally holding the lower parts of such packssnugly within their respective channels 74. The skirt portion 104 of thering member 97 has a slot 106 (FIG. 2) extending into the skirt from anupper edge of the skirt portion, the slot 106 having a width permittingmovement of the reduced end portion 77 out through the slot in adirection which is radial relative to the body 57. Accordingly when theset screw 102 is turned out and the ring member 97 is rotated to locatethe slot 106 over a particular channel 74, the lower end of the batterypack or instrument pack located in that channel can be removed. Byturning the elongated member 76 of the battery or instrument pack fromits respective terminal block 80 at the upper end, the elongated membercan be separated from the carrier device, or alternatively by removingthe screws 84, the entire unit including the terminal block 80 can beremoved.

[0036] It can be seen that the carrier device 12 provides a relativelysimple and yet rugged structure for mounting in a protected manner thesensing means, the power source and the related instrumentation forobtaining and transmitting down-hole information, but which allows readyaccess of the equipment for replacement and servicing.

[0037] The lower end portion 40 of the tubular member or section 41(FIG. 1A) is of reduced diameter and is provided with external threads107 for connection with threads 37 of tubular member 20. The tubularmember 41 has an enlarged central bore 108 which extends downwardly asubstantial distance from the upper end thereof. The upper portion ofthe enlarged bore 108 is threaded at 110 for connection to the adjacenttubular section above the apparatus 10. At the bottom of the enlargedcentral bore 108 there is a bore 112 of smaller diameter whichcommunicates with a bore 22.2 of larger diameter extending upwardly fromthe bottom end of lower end portion 41 (FIG. 1B). Received in theenlarged bore 108 is a by-pass core member 113 which has a blind centralbore 114 positioned to communicate with a central bore of the nextadjacent tubular member connected by way of threads 110. The centralblind bore 114 communicates with the space exterior of the tubularstring in the bore hole by way of radial ports 115. Extending upwardlyfrom the bottom of the core is a blind bore 116 which is incommunication with the bore 112 extending to the bottom of the tubularsection 41. A supplementary, longitudinal passage 117 communicates withthe blind bore 116 and the space adjacent the upper end of blind wherebyfluid pressure within the bore 116 can be evacuated into the wellborehole outside of port 114 the tubular string.

[0038] Extending from the bottom of the tubular member 41 to below thetubular member 92 is a by-pass tube 120, which is connected byinsulating means to the tubular member 41, and is formed of a material,such as a high strength non conductive plastic. The by-pass tube 120provides a fluid passageway 121 past the apparatus 10. As shown in FIG.1B the upper end of the tube 120 is externally threaded at 122 and isscrewed into an insulating collar 123 which may be formed, for example,of Teflon. The lower exterior surface of collar 123 is tapered inwardly.A retainer 124 which has a matching tapered interior bore 125 andexterior threads 126 is turned into interior threads 127 within bore 112at the bottom of tubular member 41. The collar 123 is received in theretainer and thus fastens the upper end of the tube 120 to the bottom oftubular member 41 and places the passageway 121 in communication withinthe passage 117. A tubular member of the same structure as 41, whichprovides a by-pass coupler at the upper end of apparatus 10 may beconnected by way of threads 93 of tubular member 92 at the lower end ofthe apparatus 10 for completing the by-pass connection at that end.

[0039] The core member 113 within the central bore 180 of the tubularmember 41 is also provided with a passageway 130. This passagewaycommunicates at its upper end with the annular space 131 below the endof the tubular member next above tubular member 41, the space 131 beingin communication with a fluid source which is controlled for transmittedfluid to controlled components, such as expandable sealing packers. Thepassageway 130 communicates with the space within the interior bore 42of the tubular member 20 and outside of the exterior surface of theby-pass tube 120. This space continues to the lower end of the apparatuson the outside of the by-pass tube 120, as the interior bores of all ofthe other components through the apparatus are larger than the outsidediameter of the by-pass tube 120. At the bottom of the apparatuscommunication is made between this space and a passageway (not shown)for separately conducting the fluid to its required location, such asthe packer seal.

[0040] The by-pass tube 120 is utilized to place the space within theborehole below the apparatus in communication with the borehole abovethe apparatus. This is done via the central bore of the tubular membersdeeper in the hole which are in communication with the exterior of thetubular string through the passageway 121 of the by-pass tube 120 to thetubular member in the string above the apparatus. Accordingly, the buildup of a pressure differential, which can force the tubular stringupwardly or downwardly, is avoided.

[0041] While an embodiment of the invention has been illustrated,modifications within the spirit of the invention as defined in theappending claims, will be apparent to those skilled in the art.

1. A connector assembly for connection in a tubing string in a borehole, said connector assembly electrically insulating an upper sectionof said string above said connector assembly from a lower section belowsaid connector assembly and comprising: an outer housing member, aninner mandrel member; characterized by: said housing member havingconnection means adjacent one end of said connector assembly forend-to-end attachment of said one end to one of said upper and lowersections of said string, and an internal surface defining a taperedopening through said connection means, said internal surface of saidhousing member including an internal bore of a large diameter towardsaid one end of said housing member and an internal bore of a smallerdiameter toward the opposite end of said housing member, the taperedopening extending longitudinally from said bore of larger diameter tosaid bore of smaller diameter, said mandrel member having secondconnection means adjacent the other end of said connector assembly forattachment of said other end to the other of said upper and lowersections, said mandrel member having an exterior surface tapering from alarge diameter end portion toward said other end and terminating at acylindrical end portion defining an exterior surface of smallerdiameter, said larger diameter of said surface of said mandrel being ofgreater diameter than the bore of smaller diameter in said housingmember. said exterior surface of said mandrel member being disposedwithin said interior surface portion of said housing member andproviding a clearance between said surfaces, and an electricallynon-conducting bond material disposed within said clearance between saidsurfaces.
 2. A connector assembly as defined in claim 1, characterizedby: said connection means of said housing member including threadedmeans for connection of said housing member to a tubular memberthereabove, and said connection means of said mandrel member includes athreaded portion of said mandrel member for connection to a tubularmember therebelow.
 3. A connector assembly as defined in claim 2,characterized by: said interior surface of said housing member having acylindrical portion thereof including a plurality of circumferentiallyspaced, longitudinally extending grooves, said exterior surface of saidmandrel member having a cylindrical portion thereof disposed within butradially separated from said cylindrical portion of said interiorsurface of said housing member, said cylindrical portion of said mandrelmember having a plurality of circumferentially spaced, longitudinallyextending grooves oppositely aligned with said grooves in saidcylindrical portion of said interior surface of said housing member, anda plurality of members each disposed in an oppositely aligned pair ofsaid grooves of said portion of said interior and exterior surfaces. 4.A connector assembly as defined in claim 3, characterized by: saidmembers disposed in said grooves being rod-like members formed ofelectrically insulating material.
 5. A connector assembly as defined inclaim 4, characterized by: said longitudinally extending grooves beingof substantially semi-circular cross-section, and wherein said rod-likemembers are of substantially circular cross-section.
 6. A connectorassembly as defined in claim 3, 4 or 5, characterized by: said bondmaterial being also disposed amongst said plurality of members.
 7. Aconnector assembly of claim 2, characterized by: said connection meansof said mandrel member including an end portion extending downward belowsaid housing member and having thread means for connection to a tubularmember therebelow.
 8. A connector assembly as defined in claim 1,characterized by: an exterior cylindrical surface of said cylindricalend portion of said mandrel portion being received in an interiorcylindrical surface of said bore of smaller diameter within said housingmember, a clearance being provided between said interior cylindricalsurface and said exterior cylindrical surface, said interior cylindricalsurface having formed therein a plurality of circumferentially spaced,longitudinally extending grooves. said exterior cylindrical surfacehaving formed therein a plurality of circumferentially spaced,longitudinally extending grooves oppositely aligned with said grooves insaid interior surface of said housing member, a plurality of rod-likemembers of electrically insulating material each disposed in anoppositely aligned pair of said grooves of said portions of saidinterior and exterior surfaces.
 9. A connector assembly as defined inclaim 8, characterized by: said bond material extending into saidclearance between said cylindrical surfaces and amongst said rod-likemembers.
 10. A connector assembly as defined in claim 1, characterizedby: said connection means of said housing member including thread meanswithin said bore of larger diameter, and a first tubular member having athreaded lower end portion for threaded interconnection within said boreof larger diameter, said tubular member including upper thread means forconnection to a second tubular member thereabove.
 11. A connectorassembly as defined in claim 10, characterized by: said mandrel having acentral longitudinal bore extending therethrough and an enlarged boreextending downwardly from said larger diameter end portion andterminating at a first radial shoulder, said first tubular member havinga central bore extending therethrough with a lower end portion of saidfirst tubular member being disposed within said housing member, saidlower end portion of said first tubular member being provided with anenlarged bore extending upwardly and terminating at a second radialshoulder, a sleeve member disposed in the enlarged bores of said mandrelmember and said first tubular member, said sleeve member being formed ofelectrically insulated material and having opposite ends in abutmentwith said first and second radial shoulders.
 12. A connector assembly asdefined in claim 2, wherein an instrument carrier device including anelongated tubular member having external channels for accommodatinginstrument sensing units is located below said mandrel member and isconnected to said threaded portion of said mandrel member, said tubularmember of said carrier device having an internal passageway, saidtubular member having a third connection means at a lower end thereoffor attachment of said carrier device to an adjacent section of saidtubing string below said carrier device, and characterized by: saidmandrel member being of tubular form defining a central passagewaytherethrough, said internal passageway of said carrier devicecommunicating at an upper end with said passageway in said mandrelmember.
 13. A connector assembly as defined in claim 12, characterizedby: an electrically insulated by-pass tube extending through saidpassageways of said mandrel and said carrier device and forming a fluidpassageway, said by-pass tube having fourth and fifth connection meansat upper and lower ends thereof, respectively, for connection ofopposite ends of said by-pass tube to said sections above and below saidapparatus for permitting fluid passage through said connector assemblyand said carrier device.
 14. The apparatus of claim 23, characterizedby: said central passageway in said mandrel and said tubular member ofsaid carrier device being of greater cross-section than said by-passtube whereby a space is provides exteriorly of said by-pass tube to forma second fluid passageway.
 15. The apparatus of claim 13, characterizedby: said housing member having a bore of large diameter extendingdownwardly thereinto, said connection means of said housing memberincluding a threaded interior surface of said bore of said housingmember, means received within the threaded bore of said housing meansand thereby connecting thereinto a tubular by-pass connector, saidtubular by-pass connector having a bore therein and port means forplacing said bore of said by-pass connector in communication with saidborehole containing said tubing string, means for connecting saidinsulating by-pass tube to said by-pass connector, and including meansdefining a passageway placing said by-pass tube in communication withsaid bore of said by-pass connector.
 16. The apparatus of claim 13, 14or 15, characterized said by-pass tube being formed of electricalnon-conductive material.
 17. The apparatus of claim 15, characterizedby: said means for connecting said by-pass tube to said tubular by-passconnector including an enlarged threaded bore extending upwardly intosaid tubular by-pass connector, and means engaging said connectionsmeans at the upper end of said by-pass tube for connecting said by-passtube within said enlarged threaded bore of said tubular by-passconnection.
 18. The apparatus of claim 17, characterized by: said meansengaging said connection means at the upper end of said by-pass tubebeing formed of electrical non-conducting material.
 19. A subsurfacesignal transmitting apparatus for connection into a tubing string in abore hole, said apparatus comprising; an insulation connector assembly,an instrument carrier device, said connector-assembly including an outerhousing member having a first connection means adjacent one end of theconnector assembly for attachment to an adjacent tubular section of saidstring above said connector assembly, an inner mandrel member having asecond connection means for attachment to an upper end of said carrierdevice, said mandrel member being of tubular form defining a centralpassageway from said one end to said other end of said connectorassembly, and means for electrically insulating said housing member fromsaid mandrel member; characterized by said carrier device including anelongated tubular member having external channels for accommodatinginstrument sensing units, an internal passageway in said tubular membercommunicating at an upper end with said passage-way in said mandrelmember and a lower end of said tubular member, said tubular memberhaving a third connection means at a lower end thereof for attachment ofsaid carrier device to an adjacent section of said string below saidcarrier device, and an electrically insulated by-pass tube extendingthrough said passageways of said mandrel and said carrier device andhaving fourth and fifth connection means at upper and lower endsthereof, respectively, for connection of opposite ends of said by-passtube to said sections above and below said apparatus for permittingfluid passage through said apparatus.
 20. The apparatus of claim 19,characterized by said central passageway in said mandrel and saidtubular member forming said carrier device being of greatercross-section than said by-pass tube whereby a space is providedexteriorly of said by-pass tube to form a second fluid passageway. 21.The apparatus of claim 19, characterized by said housing member has abore of large diameter extending downwardly thereinto, said connectionmeans of said housing member including a threaded interior surface ofsaid bore of said housing member, means received within the threadedbore of said housing means and thereby connecting thereinto a tubularby-pass connector, said tubular by-pass connector having a bore thereinand port means for placing said bore in communication with said boreholecontaining said tubular string, means for connecting said insulatingby-pass tube thereto, and including means defining a passageway placingsaid by-pass tube in communication with said bore of said by-passconnector.
 22. The apparatus of claim 19, 20, or 21, characterized bysaid by-pass tube is formed of electrical non-conductive material. 23.The apparatus of claim 21, characterized by said means for connectingsaid by-pass tube to said tubular by-pass connector including anenlarged threaded bore extending upwardly into said tubular by-passconnector, and means engaging said connections means at the upper end ofsaid by-pass tube for connecting said by-pass tube within said enlargedthreaded bore of said tubular by-pass connection.
 24. The apparatus ofclaim 23, characterized by said means engaging said connection means atthe upper end of said by-pass tube being formed of electricalnon-conducting material.
 25. The apparatus of claim 21, characterized bysaid housing member having an internal, surface portion taperinginwardly away from said bore of said housing member, wherein saidmandrel member has an exterior surface portion tapering inwardly from alarger end to a cylindrical portion of smaller diameter, the exteriorsurface portion of said mandrel member being disposed within theinterior surface portion of said housing member and providingtherebetween a clearance of substantially constant thickness, andwherein said means electrically insulating said housing member from saidmandrel member includes a bond material disposed within said clearanceand preventing rotation or longitudinal separation of said membersrelative to each other.
 26. A carrier device for use in a subsurfacesignal transmitting apparatus, said device including: an elongated bodymember having a generally cylindrical outer surface, and a firstconnection means at one end of said body member for attachment of saidbody member to an insulation connector assembly having an outer housingmember electrically insulated from said body member; characterized bysaid body member having defined in said outer surface a plurality oflongitudinal, channels commencing adjacent said one end and extendingtowards an opposite end of said body member, means for detachablysecuring instrument sensing units individually within said channels, anda passage extending from said channels to said one end accommodating asignal transmitting cable extending from said units for electrical,attachment to said outer housing of said insulation connector assembly.27. A carrier device as defined in claim 26, characterized by said unitsincluding a long tubular portion of a substantially constant thicknessterminating in free ends, and a detachable terminal block portion at anupper end thereof, said- portions of said units being of slightly lessthickness than the depth of the channel in which they are accommodated.28. A carrier device as defined in claim 26, characterized byinterconnecting channels between at least some of said longitudinalchannels and providing a passage for an electrically transmitting cableextending between said units.
 29. A carrier device as defined in claim27, characterized by said terminal blocks portion having a greater widththan said tubular portions, and wherein said channels have widenedportions adjacent said one end of said body member for accommodatingsaid terminal block portions.
 30. A carrier device as defined in claim29, characterized by said means for detachably securing said units insaid channels including screw means received in openings in saidterminal block portions and detachably connected to said body member.31. A carrier device as defined in claim 27, characterized by meansbeing provided for detachably securing said units within said channelsincluding a ring member encircling said body member adjacent saidopposite end, said ring overlying terminal end portions of said channeland said free ends of said tubular sections of said units for holdingsaid free ends within said channels.
 32. A carrier device as defined inclaim 32, characterized by said ring member being rotatable on said bodymember, and manually operable lock means for normally preventing therotation of said ring member.
 33. A carrier device as defined in claim32, characterized by said ring member defining a slot therein of a sizeto permit selected passage of each of the free end portions of one ofsaid units at a time radially outward of its respective accommodatingchannel upon rotation of said ring member to a position in which saidslot overlies said accommodating channel.